Tarantula taxonomy

I'm at odds trying to find good info on how the various T's are actually classified....e.g:
What separates Brachypelma from Aphonopelma? Or Grammostola?
What separates similar-looking species such as Nhandu chromatus from Acanthoscurria geniculata?
What separates Poecilotheria ornata from P. regalis?

I like to know what defines the various taxa so I can see for myself, and also learn what I am looking at.

There are still some on-going changes in taxonomy, and you can bet that some of silly games played elsewhere are played with Ts (eg splitters, lumpers, wanting-to-get-a-paper etc).

There is a seen a lot very very similar spiders even between genera.

In general for the 'wild beast' family of spiders, at least, the following seem to be some of the main points.

urticating hairs (in various locations)
tibial apohyses
palpal bulb
spermatheca
stridulatory bristles
Fovea
scopulae


I'm not really into spider taxonomy....I'd be more of fish jaw person....but if you're popping down on Saturday then the talking will be using one classic example for this as a point to take up further debate.

That hasn't really answered your question, but it has maybe given you a few hints as to where to look.

Some of the ID keys are based upon the points mentioned above.

ian